Lifting jack



A. JACKSON LIFTING JACK Feb. 4, 1941.

Filed Dec. 15, 1939 2 Sheets-Sheet 1 ALEX/S J CKSOA/ D INVENTOR. BY Wwu v ATTORNEY.

A. JACKSON LIFTING JACK Feb. 4, 1941.

2 Sheets-Sheet 2 Filed Dec. 15, 1959 K c v w W. X M E. L 4/ A w 9 m w m m ATTORNEY.

Patented Feb. 4, 1941 UNITED STATES LIFTING JACK Alexis Jackson, Rochester, N. Y., assignor to Vadim S. Makarofl, New York, N. Y.

Application December 15, 1939, Serial No. 309,324

17 Claims.

My invention is related to lifting jacks and has particular reference to portable jacks adapted for lifting various objects, and more particularly, automotive vehicles, by their axles.

My invention has for its object to provide a lifting jack which can be used for lifting such objects as axles of automotive vehicles from a relatively low elevation, as, for instance, when a tire supporting the axle is flat, the jack being of such construction that it can raise the axle to a. relatively high elevation above the ground to enable workmen to get under the body of the vehicle for work on repairs, etc. The height of the lift is determined by the length of the lifting arms between their fulcrums or points of support and the ends which support the axle. In similar jacks, as, for instance, disclosed in my patent application Serial No. 264,326, filed March 27, 1939, this length is limited by the necessity of placing the fulcrum at an intermediate point on the arm, so that a portion only of the total length of the lifting arm is used for raising the object.

In my present construction I provide lifting arms pivoted at their rear ends to a supporting frame, so that the full length of the arms is utilized for raising the object. The lifting power is furnished by a suitable motor, preferably a cylinder operated by fluid under pressure, the power being applied to the middle portions of the arms by means of a sliding member which is also pivoted to links, whose other ends are pivotally supported on an elevated rear portion of the frame. The motor is mounted on the rear portions of the arms and rises with them when it is energized and moves the sliding members forward. With this construction it is possible to make the front portion of the lift very low, since it is not encumbered by the motor or powertransmitting parts.

My invention is more fully described in the accompanying specification and drawings, in which:

Fig. 1 is an elevational view of my lifting jack in a lowered position, the raised position being indicated in dotted lines.

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1.

Fig. 3 is a top plan view of my jack.

Fig. 4 is a detail view of a locking mechanism in an operative position.

Fig. 5 is a similar view showing the locking mechanism in an inoperative position.

Fig. 6 is a front view of the locking mechanism in the operative position.

Fig. '7 is a detail view of a modified arm support.

Fig. 8 is a side view of the same, and Fig. 9 is a diagrammatic view of a modification with an electric motor.

My lifting jack consists of a frame made of longitudinal beams I joined together by a shaft 2 at the front and by a shaft 3 at the rear. The front end of the frame is supported on wheels 4 turning on the shaft 2 fitted in the beams i with a spacing tube 5. The rear end is supported on wheels 6 rotating on short shafts I extending from blocks 8 at the sides of the beams I (Fig. 2) The shaft 3 pivotally supports the rear ends of lifting arms 9. The front ends of the arms have extensions In in the form of hooks adapted to support an axle of an automobile or a similar object. The arms are joined together by a cross-bar II. The arms are preferably made of L-beams, the upper sides of which slidabiy support a cross-bar l2. The bar is retained on the arms by means of hooks l3 extending around the under sides of the upper flanges of the arms. The cross-bar I2 is pivotally connected to the front ends of supporting or lifting links or bars l4 whose rear ends are pivoted on a shaft l5.

The latter is mounted as by welding on the upper ends of posts I6 extending upward from the rear ends of the frame beams I. The middle portion of the cross-bar l2 has a sleeve ll rigid- 1y connected to the front end of a piston rod l8 whose rear end is welded to a piston l9 sliding in a cylinder 20. The latter has extension plates 2| at the front end rigidly supporting a shaft 22. The ends of this shaft are journaled in bearings 25 mounted on the upper sides of the arms 9. The rear end of the cylinder is free so that it floats on the piston and on the shaft 22. The rod l8 has a slot 23 for the shaft 22.

This arrangement has an advantage in that the piston can be rigidly connected with the piston rod, the latter being also rigidly connected to the sleeve ii on the cross-bar 12. The structure is therefore very simple and self-aligning at all times. A fluid under pressure, such as compressed air, is introduced into the cylinder through a nipple 24 connected by a flexible hose 4| with a source of the fluid (not shown). The mounting of the cylinder on the arms makes it possible to place the arms very low, thereby permitting the lift to be placed under very low parts of an automobile or under very low-positioned objects.

In the operation of the device, when compressed air is admitted into the cylinder, the

piston is moved forward, pushing the cross-bar l2 over the arms 9. Because of the triangular support of the arms on the links or bars ll, the arms are raised to a position such as is shown in dotted lines in Fig. 1.

In order to prevent the arms from falling down if the air leaks out from the cylinder, a locking mechanism is provided in the form of a yoke 26 rotatively supported on the shaft 22 around the rod l8. The yoke has a central latch 21 engaging slots 28 in the upper side of the rod l8. A spring 29 on the shaft 22 tends to turn the yoke into an operative position with the latch entering one of the slots 28.

The latch has a tapering rear side 21' which slides over the front edges of the slots 28 when the rod I8 is moved forward, the hook portion of the latch engaging the rear edges of the slots when the rod I8 is moved rearward, thereby preventing such rearward movement. For releasing the locking device or latch, it has a handle 30 extending upward. The latch can be turned away from the rod by the handle and can be locked in the inoperative position by allowing a lug 3| on the yoke to engage a hook end 32 of a spring 33 supported on the upper side of the cylinder. The latch is automatically released by lugs or pins 34 on thefront end of the piston rod 3 when the piston is moved back into the cylinder, the pins 34 turning the yoke on the shaft 22 and pushing the lug 3| out of engagement with the hook 32 of the spring 33.

In order to reduce the friction between the hooks I3 and the arms, rollers 35 may be provided as shown in Fig. 7, the rollers engaging the under sides of the upper flanges of the arms and being rotativelymounted on short shafts 36 extending from the sides of yokes 31 mounted on the cross-bar l2.

The cylinder may be replaced by an electric motor 38 as shown in Fig. 8, the motor operating a. screw 39 engaging a threaded hole in the middle portion of a cross-bar 10, corresponding to the cross-bar l2. With the electric motor it is not necessary to have a separate locking mechanism since .the screw is self-locking.

It is understood that my lifting jack may be further modified without departing from the spirit of the invention as set forth in the ap-' pended claims.

I claim as my invention:

1. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at theirfront ends, posts mounted on the rear ,end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, means to slidably support the front ends of the bars on the arms, a motor mounted on the arms, and means to move the bar supporting means on the arms forward, .thereby causing the front ends of the arms to be raised. a l

2. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the'arms, the front ends of the bars being pivotally supported on the crossbar, a moframe, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward,

bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a

motor mounted on the crossbar, a member extending from the motor to the crossbar, and means to move the crossbar forward by the motor, thereby raising the arms.

4. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a cylinder mounted on the rear portions-of the arms, a piston-in the cylinder, a member connecting the piston with the crossbar, and means to admit a fluid under pressure into the cylinder for moving the piston and thereby raising the arms.

5. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, an electric motor mounted on the arms, and a screw means to move the crossbar forward by the motor for raising the'arms.

6. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear .end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar. slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a cylinder mounted on the arms, a piston in the cylinder, a piston rod rigidly connected withthe piston and with the crossbar, and means to admit a fluid under pressure into the cylinder for moving the crossbar forward thereby raising the 7. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the 7 into the cylinder for moving the crossbar forward, thereby raising the arms, the rod having notches, a shaft connecting the arms in front of the cylinder, a locking latch movablysupported on the shaft adapted to engage the notches for preventing rearward movement of the crossbar, and manually operable means to render the latch inoperative.

8. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends ofjthe bars being pivotally supported on the crossbar, a cylinder mounted on the arms, a piston 'in the cylinder, a piston rod extending from the piston to the crossbar, means to admit fluid under pressure into the cylinder for moving the crossbar forward, thereby raising the arms, the rod having notches, a shaft connecting the arms in front of the cylinder, a locking latch movably supported on the shaft adapted to engage the notches for preventing rearward movement of the crossbar, manually operable means to render the latch inoperative, and means on the rod to render the latch operative when the crossbar is moved to its extreme rear position.

9. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a cylinder mounted on the arms, a piston in the cylinder, a piston rod extending from the piston to the crossbar, means to admit fluid under pressure into the cylinder for moving the crossbar forward, thereby raising the arms, the rod having notches, a shaft connecting the arms in front of the cylinder, a locking latch movably supported on the shaft adapted to engage the notches for preventing rearward movement of the crossbar, manually operable means to render the latch inoperative, yieldable means to retain the latch in the inoperative position, and means to render the latch operativewhen the crossbar is moved to its extreme rear position.

10. A' lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on'the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a cylinder mounted on the arms, a piston in the cylinder, a piston rod extending from the piston to the crossbar, means to admit fluid under pressure into the cylinder for moving the crossbar forward, thereby raising the arms, the rod having notches, a shaft connecting the arms in front of the cylinder, a locking latch movably supported on the shaft, yieldable means to urge the latch against the notches for preventing the rearward movement of the crossbar, means to manually render the latch inoperative, and means to render the latch operative when the crossbar is moved into its rear position.

11. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends 5 of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the 10 upper portions of th posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar,

a cylinder mounted on the arms, a piston in the cylinder, a piston rod extending from the piston 15 to the crossbar, means to admit fluid under pressure into the cylinder for moving the crossbar forward, thereby raising the arms, the rod having notches, a shaft connecting the arms in front of the cylinder, a locking latch rotatively sup- 0 ported on the shaft, yieldable means to urge the latch against the notches for preventing the rearward movement of the crossbar, the latch being adapted to be manually turned into inoperative position, yieldable means to retain the latch in 28 the inoperative position, and means to release the latch at the end of the rearward movement of the crossbar.

12. A lifting jack comprising an elongated frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a cylinder, means to rotatively support the cylinder on the arms, a piston in the cylinder, a rod connect- 40 ing the piston with the crossbar, means to prevent the rearward movement of the crossbar, and means to render the movement preventing means inoperative.

13. A lifting jack comprising an elongated 45 frame, wheels supporting the front and rear ends of the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, 60 bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a cylinder, means to relatively support the front end of the cylinder on the arms, a. piston in the cylinder, a rod connecting the piston with the crossbar having an elongated opening for the shaft, means to prevent the rearward movement of the crossbar, and means to render the 60 movement preventing means inoperative.

14. A lifting jack comprising an elongated frame, wheels supporting the front and rear endsof the frame, arms pivotally supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar slidably supported on the arms, the front ends of the bars being pivotally supported on the crossbar, a shaft rotatively supported at its ends on the middle portions of the arms, a cylinder mounted at its open end on the shaft and extending rearward,

a piston in the cylinder, a rod connecting the piston with the crossbar having an elongated opening for the shaft, 9. locking latch rotativeiy mounted on the shaft, the rod having notches for the latch, yieldable means to pres the latch against the notches for preventing the rearward movement of the crossbar, a resilient member on the cylinder adapted to yieldably engage the latch in its inoperative position, and projections on the rod adapted to move the latch into the operative position at the end of the rearward movement of the crossbar.

15. A lifting jock comprising an elongated frame, arms pivotally'supported at the rear end of the frame adapted to support an object at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear'ends on the upper portions of the posts, means to slidably support the front ends of the bars on the arms, and means on the arms to move the bar supporting means on the arms forward, thereby causing the front ends of the arms to be raised.

16. A lifting jock comprising and elongated frame, arms pivotally supported at the rear end of the frame adapted to support an object-"at their front ends, posts mounted on the rear end of the frame and extending upward, bars pivotally supported at their rear ends on the upper portions of the posts, a crossbar siidably supported on the arms, the front ends of the arms being pivotally supported on the crossbar, and means on the arms to move the crossbar forward,'thereby raising the arms.

17. A lifting jack comprising an elongated frame, a movable member pivotally supported at the rear end of the frame adapted to support an object at its front portion, an upwardly extending supporting member .on the rear end of the frame, an upper member pivotally supported at its rear end on the upper portion of the upwardly extending supporting member, means to slidably support the front end of the upper member on the movable member, and means on'the movable member to move the upper member supporting means on the movable member forward, thereby causing the front end of the movable member to be raised.

. ALEXIS JACKSON. 

